\begin{tikzpicture}[>=Stealth]
    \draw [->] (-1.3,0) -- (5.5,0);
    \foreach \x in {-1,-0.5,...,4.5} {
        \draw (\x,0.2) -- (\x,0);
    }

    \foreach \pos/\text in {0/0, 1/+2, 3/+6} {
        \node at (\pos, 0) [below] {$\text$};
    }
\end{tikzpicture}
